Biogrânulos aeróbicos em reator seqüencial em batelada para o tratamento de efluente de biodigestor proveniente da suinocultura

Abstract

The fermentation of pig slurry into anaerobic digesters has been a recommended practice for the energetic utilization of the produced methane (CH4), thus reducing the emission of this greenhouse gas into the atmosphere. However, the wastewater (effluent of the digester), if dumped in the current water, can cause pollution because it has Chemical Oxygen Demand (COD) and ammoniacal N levels higher than the slurries in natura, besides the phosphorus, presence of odor and pathogens. This study had as objective to evaluate the efficiency of a sequential batch reactor (SBR) of aerobic biogranules in the treatment of anaerobic digester effluents fed with pigs slurry. For that, a study was done in the Soil and Environmental Microbiology Laboratory, in Universidade Federal de Santa Maria, Santa Maria RS, Brazil. The SBR was operated for 88 days, with three daily cycles of 8 h, with different sequential stages: without air supply, with air supply and without air supply. During this period the efficiency of the process in the removal of the COD, Total Kjeldahl Nitrogen (TKN), nitric N and ammoniacal N, total Phosphorus (total P), Total Solids (TS), pH and odor were evaluated. The removal efficiency was of 52% for COD, 37% for total P and approximately 72% for TKN, ammoniacal N and TS. The effluent of the reactor did not show noticeable odor. The nitrification was the major process in the removal of the ammoniacal N during the treatment in aerobic granules reactor of the wastewater from anaerobic digestion of pigs slurries. Although the resulting effluent still needs a post-treatment to be dumped in the environmental, the use of aerobic biogranules in SBR showed to be a promising biotechnology for the pollutant removal of the evaluated wastewater.